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4105032 | Paracrystalline sheets reaggregated from solubilized exosporium of Bacillus cereus. | Fragments of exosporium, isolated from dormant spores of Bacillus cereus, were disintegrated by treatment with sodium dodecyl sulfate (SDS) or with phenol and acetic acid. After centrifugation of each preparation, proteins in the supernatant fractions were resolved by disc gel electrophoresis into either two or eight b... |
4934519 | A translocation-associated ribosomal conformational change detected by hydrogen exchange and sedimentation velocity. | Translocation in ribosomes consists of transposition of peptidyl-tRNA from the aminoacyl to the peptidyl site and, probably concomitantly, the movement of ribosomes on mRNA. Does a conformational change in the ribosome provide the motive force for this process? Hydrogen exchange and sedimentation velocity experiments i... |
4104295 | Cell surface immunoglobulin. II. Isolation and characterization of immunoglobulin from mouse splenic lymphocytes. | The proteins on surfaces of living splenic lymphocytes from normal BALB/c mice were iodinated enzymatically. Such cells were fractionated into two sub-populations: one composed almost exclusively of small lymphocytes and the other mainly of large lymphocytes and plasma cells. Specific immunoprecipitation of radiolabele... |
4325001 | Deficiency of uncoupler-stimulated adenosine triphosphatase activity in tightly coupled hepatoma mitochondria. | Tightly coupled mitochondria from the well-differentiated hepatoma 7800 failed to exhibit a significant 2,4-dinitrophenol-activated ATPase activity at concentrations of uncoupler sufficient to completely inhibit oxidative phosphorylation. ATPase activity could not be maximally activated by uncoupling agents more potent... |
4995064 | Synthesis and assembly of immunoglobulins by malignant human plasmacytes and lymphocytes. II. Heterogeneity of assembly in cells producing IgM proteins. | Bone marrow or lymph node cells from 10 patients whose sera contained large amounts of monoclonal IgM proteins were incubated with radioactive amino acids in short-term tissue culture. Samples of soluble cytoplasmic extracts and secreted material were examined by immunologic precipitation with specific antisera, acryla... |
4256564 | The subunits of chemically treated proteoglycan isolated from bovine nasal cartilage. | 1. The light fraction of the proteoglycan of bovine nasal cartilage was split by treatment with 0.1m-hydrochloric acid in acetone. The products were separated by gel filtration on 4% agarose and two retarded fractions were detected and isolated. These two fractions were found to have a Stokes radius of 134 and 47 A res... |
4993385 | Electron spin resonance of chlorophyll and the origin of signal I in photosynthesis. | A comparison has been made between Signal I, the photo-electron spin resonance signal associated with the primary light conversion act in photosynthesis, and free-radical signals generated in various chlorophyll species in vitro. The esr signals obtained from chlorophyll.monomer, (Chl.L)(+.), chlorophyll dimer, (Chl(2)... |
5543437 | Mutants in a nonessential gene of bacteriophage T4 which are defective in the degradation of Escherichia coli deoxyribonucleic acid. | Wild-type bacteriophage T4 was enriched for mutants which fail to degrade Escherichia coli deoxyribonucleic acid (DNA) by the following method. E. coli B was labeled in DNA at high specific activity with tritiated thymidine ((3)H-dT) and infected at low multiplicity with unmutagenized T4D. At 25 min after infection, th... |
4509330 | Assembly of rod-shaped virus in vitro: reconstitution with cucumber green mottle mosaic virus protein and tobacco mosaic virus RNA. | In vitro assembly of tobacco mosaic virus (TMV) from its constituent RNA and protein occurs in two steps: formation of the initial complex by interaction of the 5'-end of TMV-RNA with 20S protein aggregate, and growth of the helical rod by sequential addition of protein subunits.Such a process was also observed in the ... |
4345493 | Thermosensitive block of the Sabin strain of poliovirus type I. | The thermosensitive defect of the Sabin LSc2ab strain of poliovirus type I was studied. Transfer of infected KB cells from 36 to 38.5 C resulted in 30% inhibition of viral RNA replication but in 90% inhibition of formation of virions. Neither 74S procapsids nor 14S particles were detected in the cells transferred to th... |
4198082 | Sporulation in Bacillus subtilis. Properties and time of synthesis of alkali-soluble protein of the spore coat. | An alkali-extractable protein fraction comprising 6% of the dry weight of the spore can be removed from spores of Bacillus subtilis 168. Three different extraction procedures each yield at least one similar protein. Extracted protein behaved as a single species on ion-exchange chromatography or gel filtration, but two ... |
4563986 | Cell wall peptidoglycan mutants of Escherichia coli K-12: existence of two clusters of genes, mra and mrb, for cell wall peptidoglycan biosynthesis. | Temperature-sensitive mutants of Escherichia coli K-12 which cannot form cell wall peptidoglycan at 42 C were isolated. The thermosensitive steps were characterized biochemically, and the genes coding the enzymes of peptidoglycan synthesis were mapped. These genes were in two clusters: one group, located at about 1.5 m... |
4538974 | Molecular events accompanying the fixation of genetic information in Haemophilus heterospecific transformation. | Heterospecific transformation between Haemophilus influenzae and H. parainfluenzae was investigated by isopycnic analysis of deoxyribonucleic acid (DNA) extracts of (3)H-labeled transforming cells that had been exposed to (32)P-labeled, heavy transforming DNA. The density distribution of genetic markers from the reside... |
4507618 | Addition of chemical and osmotic free energies through negative interaction of protein-bound ligands. | Simple free energy considerations show that an effector ligand, Y, bound to a protein can modify the standard free energy change of the reaction P - X + D - R = P - R + D - X, where P is a protein, D - R a small molecule, and X a group in the protein that interacts negatively with Y. By consideration of a three-compart... |
4559819 | Kinetics of deoxyribonucleic acid destruction and synthesis during growth of Bdellovibrio bacteriovorus strain 109D on pseudomonas putida and escherichia coli. | During the growth of Bdellovibrio bacteriovorus on Pseudomonas putida or Escherichia coli in either 10(-3)m tris(hydroxymethyl)aminomethane or in dilute nutrient broth, the host deoxyribonucleic acid (DNA) was rapidly degraded, and by 30 to 60 min after the initiation of the bdellovibrio development cycle essentially a... |
4559740 | Cell division mutations in the blue-green bacterium Agmenellum quadruplicatum strain BG1: a comparison of the cell wall. | The peptidoglycan from two types of filamentous cell division mutants of Agmenellum quadruplicatum strain BG1 has been compared to that of the parent organism. Small variations in the total peptidoglycan composition on a dry-weight basis were found in the mutants. The reduced level of peptidoglycan in the serpentine mu... |
4506097 | Interactions between native and chemically modified subunits of matrix-bound glycogen phosphorylase. | Phospho-dephosphohybrids of rabbit skeletal muscle phosphorylase (EC 2.4.1.1; alpha-1,4-glucan: orthophosphate glucosyl transferase) have been prepared and stabilized by attachment to Sepharose activated by cyanogen bromide. They can be distinguished from phosphorylase a by their sensitivity to inhibition by glucose-6-... |
5040863 | The form and structure of kinetoplast DNA of Crithidia. | Cesium chloride centrifugation of each of the DNAs extracted from eight strains of Crithidia revealed a main band at rho = 1.717 g/cm(3) and a satellite band varying from rho = 1.701 to 1.705 g/cm(3) for the different strains By electron microscopy each DNA was shown to include circular molecules, 0.69-0.80 micro in me... |
4505672 | Electron microscope studies of heteroduplex DNA from a deletion mutant of bacteriophage phiX-174. | A population of double-stranded replicative form of DNA molecules from bacteriophage varphiX-174 carrying a deletion of about 9% of the wild-type DNA has been discovered in a sample cultivated under conditions where the phage lysozyme gene is nonessential. The structures of deleted monomers, dimers, and trimers were st... |
4505671 | Relaxation study of complex formation between monovalent cations and cyclic polyethers. | Equilibrium quotients for the 1:1 complexes of dibenzo-30-crown-10 with Na(+), K(+), Rb(+), Cs(+), NH(4) (+), and T1(+) in methanol solution have been determined spectrophotometrically. The observed selectivity pattern is discussed in terms of the hydration energy of the cations and the cation-ligand binding energy. Th... |
4558661 | RNA-linked nascent DNA fragments in Escherichia coli. | Nucleic acid that is extracted from E. coli labeled by a brief pulse of [(3)H]dT and depatured by treatment with heat, formamide, or formaldehyde bands in a region with a density higher than that of single-stranded E. coli DNA in a Cs(2)SO(4) equilibrium density gradient. If treated with alkali or RNase, it then exhibi... |
4338745 | The fragments of the photosynthetic electron transfer chain in model systems. | In this paper the recent research from our laboratory is reviewed. Short fragments of the photochemical electron transfer chain of photosynthesis were reproduced in aqueous detergent solutions or in organic solvents. The function of photosystem I is reproduced in a ternary system of chlorophylls, electron donors (dieno... |
4504368 | Transfecting deoxyribonucleic acid of Bacillus bacteriophage phi 29 that is protease sensitive. | The transfecting activity of Bacillus phage varphi29 DNA, extracted either by sodium lauroyl sarcosine-phenol or by 2 M perchlorate, was destroyed by treatment with proteolytic enzymes, although these enzymes did not effect transfecting DNAs of SPP1, SPO1, and SP50. These facts suggest that a protein is associated with... |
4624112 | Extracellular alkaline amylase from a Bacillus species. | A selective medium was used to isolate a bacterium (Bacillus species NRRL B-3881) that produced extracellular alkaline amylase in an alkaline medium (pH 9.5). Maximal enzyme yield was obtained in an aerated medium after 21 hr at 36 C. The enzyme was purified 18-fold by ultrafiltration and ammonium sulfate precipitation... |
4554989 | Translational mobility of the membrane intercalated particles of human erythrocyte ghosts. pH-dependent, reversible aggregation. | This paper demonstrates the translational movement along the plane of the human erythrocyte ghost of the membrane particles exposed by freeze-fracture. The membrane particles can be aggregated by incubation of the ghosts in media with a pH in the vicinity of 5 5 or 3 5. The particles are disaggregated in neutral and al... |
5025439 | Cell surface immunoglobulin. 3. Isolation and characterization of immunoglobulin from nonsecretory human lymphoid cells. | Cells from an established line of Burkitt lymphoma (Daudi) were enzymatically radioiodinated, and labeled Ig from the cell surface was isolated and studied. Subcellular fractionation of labeled cells confirmed that intracellular proteins from the cytoplasm are not iodinated by this method. Radioactive Ig was identified... |
5025493 | Coordinate variation in lengths of deoxyribonucleic acid molecules and head lengths in morphological variants of bacteriophage T4. | We have investigated three classes of small bacteriophage T4 particles which differ from normal T4 particles in length of their deoxyribonucleic acid (DNA), in head length, in protein content, and in density. The different particles contain DNA molecules measuring 0.90, 0.77, or 0.67, respectively, of the normal T4 len... |
4260278 | Repetitive sequences in the murein-lipoprotein of the cell wall of Escherichia coli. | The amino-acid sequence of the murein-lipoprotein of the Escherichia coli cell wall is presented. This protein is covalently bound to a lipid component as well as to the murein (peptidoglycan, mucopeptide). The sequence is also highly repetitive. At the N-terminal portion, there are three adjacent almost identical sequ... |
4552994 | Comparative chemistry of 30S ribosomal proteins of Salmonella typhimurium. | Individual proteins from the 30S ribosome of Salmonella typhimurium were isolated and compared with their counterparts in Escherichia coli. Amino acid composition data reveal either no significant differences, or only minor differences in a few residues between paired proteins. Tryptic peptide fingerprints were used to... |
4622900 | Regulation of the bacterial cell wall: analysis of a mutant of Bacillus subtilis defective in biosynthesis of teichoic acid. | Bacillus subtilis 168ts-200B is a temperature-sensitive mutant of B. subtilis 168 which grows as rods at 30 C but as irregular spheres at 45 C. Growth at the nonpermissive temperature resulted in a deficiency of teichoic acid in the cell wall. A decrease in teichoic acid synthesis coupled with the rapid turnover of thi... |
4672507 | Immunochemical studies on human calcitonin M leading to information on the shape of the molecule. | 1. Two antisera were obtained from a single rabbit. Both are highly specific for human calcitonin M but react with different parts of the amino acid sequence. 2. The different sequences that react with the antibodies of the two antisera were located. The first antiserum reacts at two sites in the molecule, one in the s... |
5073721 | Isolation of human synovial-fluid hyaluronate by density-gradient ultracentrifugation and evaluation of its protein content. | 1. A compound of hyaluronate and protein, called hyaluronate-protein was isolated from pooled human synovial fluids by caesium chloride density-gradient ultracentrifugation. 2. The isolated hyaluronate-protein was labelled with [(125)I]iodide and the following studies were done. (a) Ultracentrifugation in caesium chlor... |
4501588 | Replication of mitochondrial DNA. Circular replicative intermediates in mouse L cells. | The frequency, composition, and structure of circular replicating forms of mitochondrial DNA, including two new forms described here, suggest a scheme for the mode of replication of this DNA. |
5062884 | Solid-phase radioimmunoassay of total and influenza-specific immunoglobulin G. | An antigen-antibody system of polystyrene tubes coated with immunoglobulin antibody was used for quantitating immunoglobulins. A similar radioimmunoassay method was adapted for a viral antigen-antibody system. The viral system can be used for quantitating viruses and for measuring virus-specific antibodies by reacting ... |
4552417 | Bacteriophage T4 head morphogenesis. II. Studies on the maturation of gene 49-defective head intermediates. | An investigation into the metabolic requirements for maturation of gene 49-defective heads indicated that adenosine triphosphate energy and continued deoxyribonucleic acid (DNA) but not ribonucleic acid synthesis were needed. The fate of DNA present at restrictive temperatures (41.5 C) in tsC9 (gene 49)-infected cells ... |
5060293 | Studies on antibody affinity at the cellular level. Correlation between binding properties of secreted antibody and cellular receptor for antigen on immunological memory cells. | Heterogeneity with regard to affinity of anti-hapten antibody was demonstrated at the cellular level in mice. The heterogeneity was shown at the level of single antibody-forming cells using hapten inhibition of hemolytic antibody plaque formation as a measure of affinity. The affinity increased with time after immuniza... |
4110147 | Isolation, characterization, and ultrastructure of the peptidoglycan layer of a marine pseudomonad. | The peptidoglycan layer of a marine pseudomonad was observed by electron microscopy in thin sections of plasmolyzed intact cells and mureinoplasts but not in untreated intact cells. Only fragments of this layer could be isolated by sodium lauryl sulfate (SLS) treatment of mureinoplast envelopes. Sacculus-like peptidogl... |
4559465 | Immunological determination of Mycobacterium leprae by means of cytoplasmic antigens. | Mycobacterium leprae was isolated and purified from lepromas, the spleen, and the liver of leprosy patients. An immunodiffusion analysis of the cytoplasms obtained from four lots of M. leprae and M. lepraemurium, 295 strains of different actinomycetales, and 12 other bacteria was performed with the use of the cytoplasm... |
4550781 | Mechanism of adsorption and eclipse of bacteriophage phi X174. I. In vitro conformational change under conditions of eclipse. | Bacteriophage phiX174 undergoes a conformational change during viral eclipse when virus-host cell complexes are incubated briefly at 37 C in a complex starvation buffer at pH 8. In this report, basically the same transition is demonstrated in vitro. Incubation of phiX alone for 2 to 3 hr at 35 C in 0.1 m CaCl(2) (pH 7.... |
4631043 | Cultivation techniques for the erythrocytic stages of malaria parasites. | The study of the biochemistry, physiology, and immunology of plasmodia has been restricted by the difficulty of maintaining the parasites in isolation from the host. Some success has been achieved in cultivating them in vitro, using tissue cultures and chick embryo techniques to study exoerythrocytic states and the spo... |
4521218 | Stereochemical trigger for initiating cooperative interaction of the subunits during the oxygenation of cobaltohemoglobin. | Relative to the standard provided by an unconstrained five-coordinate imidazoleiron(II) porphyrin, the axial separation (N(epsilon)...P(mu)) in deoxyhemoglobin of the complexed histidine-nitrogen (N(epsilon)) atom from the mean plane (P(mu)) of the protoporphyrin is stretched by [unk] 0.30 A. Retention of the same glob... |
4519656 | Manipulation of fatty acid composition in animal cells grown in culture. | The fatty acid composition of animal cells cultured in serum-free medium can be manipulated when the synthesis of endogenous fatty acids is inhibited by a biotin analog and fatty acids are supplied in the medium as detergent esters of Tween. When mouse LM cells were grown in medium supplemented with Tween-19:0 (an este... |
4202844 | The presence of ribonucleotides in mature closed-circular mitochondrial DNA. | Mitochondrial DNA from mouse and HeLa cells is nicked by alkali and chick-embryo ribonuclease H. It has been concluded that ribonucleotides are present in the closed-circular duplex. A comparative study of the scission rates at pH 13.0 of RNA and of mitochondrial DNAs indicates that there are no more than 10 ribonucleo... |
4761337 | Secretory protein synthesis in the stimulated rat parotid gland. Temporal dissociation of the maximal response from secretion. | Administration of the beta-adrenergic drug, isoproterenol (IPR), affects the release of 98% of stored amylase from rat parotid gland acinar cells. A period of 6 h elapses from the onset of secretion to the maximum [(14)C]phenylalanine (Phe) incorporation into total protein and amylase. 10 h after IPR administration the... |
4761334 | The fine structure and immunological labeling of the achromatic mitotic apparatus after disruption of cell membranes. | After treatment of HeLa and L cells with vinblastine sulfate the material of microtubules (tubulin) was reorganized into (a) large paracrystals (PC) of tightly packed tubules; (b) smaller aggregates of tubules with greater diameter whose walls are constituted from well defined, helically arranged morphological subunits... |
4127630 | Freeze-etching of the cell envelope of an Acinetobacter species which carries a regular array of surface subunits. | Freeze-etching was applied to preparations, with and without glycerol, of Acinetobacter sp. strain MJT/F5/199A, consisting of intact cells after normal growth or after incubation with chloramphenicol, spheroplasts, and isolated cell walls and outer membranes. Etched preparations show that a regular array of subunits fo... |
4141707 | Anionic sites of human erythrocyte membranes. II. Antispectrin-induced transmembrane aggregation of the binding sites for positively charged colloidal particles. | The effects of affinity-purified antispectrin gamma-globulins on the topographic distribution of anionic residues on human erythrocytes membranes was investigated using collo ida iron hydroxide labeling of mounted, fixed, ghost membranes. Antispectrin gamma-globulins were sequestered inside ghosts by hemolysis and the ... |
4217800 | Glutaraldehyde fixation of isolated eucaryotic nuclei. Evidence for histone-histone proximity. | Isolated chicken erythrocyte nuclei have been incubated with dilute concentrations of the bifunctional cross-linking agent glutaraldehyde (0-20 mM) in order to stabilize histone-histone interactions within the native nucleus. The kinetics of the disappearance of acid-soluble histones, free amino groups, and of individu... |
4594034 | Effect of circularity and superhelicity on transcription from bacteriophagelambda DNA. | We studied RNA synthesis in vitro from closed-circular lambda DNA molecules with varying degrees of superhelicity. The four circular templates examined had 0, -50, -110, and -160 superhelical turns under the conditions of the transcription assay. We found that the total amount of RNA synthesis increases as the template... |
4205352 | Biosynthesis of immunoglobulin A (IgA) and immunoglobulin M (IgM). Requirement for J chain and a disulphide-exchanging enzyme for polymerization. | Mouse myeloma cells secreting 19S IgM (immunoglobulin M) (MOPC 104E and TEPC 183) or monomer and polymer IgA (immunoglobulin A) (MOPC 315) were incubated with radioactive leucine and the intracellular and secreted immunoglobulins and immunoglobulin subunits were prepared by preparative sucrose-density-gradient centrifu... |
4765397 | Physical and chemical properties of Trichoplusia ni granulosis virus granulin. | The protein solubilized from the proteinic crystalline structure surrounding the granulosis virus of Trichoplusia ni by use of a carbonate buffer (pH 10.7) gives a major component, as analyzed by ultracentrifugation, with a molecular weight of 180,000. This protein has heterogeneous subunit structure as demonstrated by... |
4745432 | Occurrence of cell lytic enzymes in blue-green bacteria. | Detergent extracts of three blue-green bacteria (Agmenellum quadruplicatum strain BG1, Anacystis nidulans strain TX20, and Nostoc sp. strain MAC) contained enzymes capable of lysing suspensions of Micrococcus lysodeikticus. The enzyme preparation from A. quadruplicatum released soluble reducing fragments from purified ... |
4200858 | Development of ultraviolet resistance in sporulating Bacillus cereus T. | Ultraviolet (UV) resistance patterns of sporulating Bacillus cereus were determined. Six different categories of UV resistance were discernible as the organism progressed from exponential growth to the free, mature spore. Light microscope observations allowed the assignment of certain sporulation stages to specific UV ... |
4490525 | Absence of circular plasmid deoxyribonucleic acid attributable to a genetic determinant for methicillin resistance in Staphylococcus aureus. | Plasmid deoxyribonucleic acid was not detected by centrifugal analysis of lysates of penicillinase-negative strains of Staphylococcus aureus harboring a determinant of methicillin resistance derived from strain Villaluz. When these strains contained a penicillinase plasmid, the plasmid deoxyribonucleic acid of methicil... |
4270447 | In vitro formation of nitrate reductase using extracts of the nitrate reductase mutant of Neurospora crassa, nit-1, and Rhodospirillum rubrum. | In vitro formation of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate reductase (NADPH: nitrate oxido-reductase, EC 1.6.6.2) has been attained by using extracts of the nitrate reductase mutant of Neurospora crassa, nit-1, and extracts of either photosynthetically or heterotrophically grown Rhodospir... |
4517950 | Collagen synthesis: a disulfide-linked collagen precursor in chick bone. | Chick calvaria labeled in vitro contain a triple-stranded collagen precursor that contains two pro alpha1 and one pro alpha2 chains. All chains contain cystine and are linked by S-S bonds. Ultracentrifugal analysis was used to measure the relative size of the disulfide-linked units. It is proposed that the S-S links he... |
4365369 | Lateral phase separations in membrane lipids and the mechanism of sugar transport in Escherichia coli. | Changes in slope of Arrhenius plots for transport can, in some instances, be detected at two different temperatures for cells that have a relatively simple fatty-acid composition in the membrane lipids. These characteristic temperatures correlate with the characteristic temperatures that define changes of state in memb... |
4201304 | The interaction of alpha 2-macroglobulin with proteinases. Characteristics and specificity of the reaction, and a hypothesis concerning its molecular mechanism. | 1. alpha(2)-Macroglobulin is known to bind and inhibit a number of serine proteinases. We show that it binds thiol and carboxyl proteinases, and there is now reason to believe that alpha(2)-macroglobulin can bind essentially all proteinases. 2. Radiochemically labelled trypsin, chymotrypsin, cathepsin B1 and papain are... |
4355933 | Polypeptide composition of poliovirions, naturally occurring empty capsids, and 14S precursor particles. | The three serotypes of poliovirus were compared with respect to their polypeptide composition. Type 1, 2, and 3 strains were clearly different from each other in the electrophoretic mobilities of their larger structural polypeptides. Some of the viral polypeptides formerly identified as single peaks (e.g., VP 2) were s... |
4719679 | The membrane attack mechanism of complement. Verification of a stable C5-9 complex in free solution. | The membrane attack mechanism of complement, C5 to C9, has previously been postulated to associate on the target cell surface to a stable decamolecular complex with a calculated mol wt of 995,000. A soluble and stable complex consisting of C5, C6, C7, C8, and C9 has now been demonstrated to arise as a consequence of co... |
4749275 | Insulin biosynthesis in the bullhead, Ictalurus nebulosus, and the effect of temperature. | Insulin biosynthesis in the brown bullhead, Ictalurus nebulosus (Le Sueur), was studied by measuring the incorporation in vitro of [(3)H]leucine into proteins of the principal islet. The tissue was incubated for 6-15h in Krebs-Ringer bicarbonate buffer with [(3)H]leucine, supplemented with amino acids and glucose. Prot... |
4352970 | Activation of a covalent enzyme-substrate bond by noncovalent interaction with an effector. | The absorption spectrum of an activesite specific chromophoric acyl enzyme, sturgeon beta-(2-furyl)-acryloyl-glyceraldehyde-3-phosphate dehydrogenase, is reported. This acyl enzyme undergoes all of the catalyzed reactions characteristic of the intermediate of the physiological acyl enzyme, 3-phospho-D-glyceroyl-glycera... |
4579010 | Cell envelope and shape of Escherichia coli K12. | Rod-shaped "ghosts" that are free of murein have been isolated from E. coli. The shape of these "ghosts" is maintained by a unit membrane soluble in sodium dodecyl sulfate. Ghosts consist of about 20-30% phospholipid (almost exclusively phosphatidylethanolamine) and 50-60% protein; a large fraction of the remaining mat... |
4577739 | Ambiguity in a polypeptide-synthesizing extract from Saccharomyces cerevisiae. | Environmental factors known to induce ambiguity in bacterial extracts were tested in an in vitro cytoplasmic polypeptide-synthesizing system derived from Saccharomyces cerevisiae. Increasing concentrations of magnesium, spermine, and spermidine resulted in extensive leucine-phenylalanine ambiguity in polyuridylic acid-... |
4197274 | Extractable lipids of gram-negative marine bacteria: phospholipid composition. | Phospholipid compositions of 20 strains of marine and estuarine bacteria were determined. Results showed that phospholipids of marine bacteria differed very little from those of nonmarine organisms with phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol being the predominant phospholipids in all... |
4123237 | Isolation of outer membranes with an ordered array of surface subunits from Acinetobacter. | A method has been developed for the isolation of outer membranes from Acinetobacter sp. strain MJT/F5/199A. Washed cells were broken in a French press and, after deoxyribonuclease and ribonuclease treatment, removal of intact cells, and four washes in 20 mosmol phosphate buffer, pH 7.4, with centrifugation at 25,000 x ... |
4736510 | Analysis of Halobacterium halobium gas vesicles. | Gas vesicles, isolated from lysed Halobacterium halobium cells, gave an amino acid analysis which accounted for 78% of the weight, and the balance was mainly salt and water. One percent of tightly bound d-galactose was found, as well as 2% of phosphate that was not released by treatment which promotes beta-elimination,... |
17248611 | Mutational Analysis of Mating Type Inheritance in Syngen 4 of PARAMECIUM AURELIA. | Six genic mutations restricting clones to mating type VII (O) were isolated in syngen 4, Paramecium aurelia. The only three extensively tested were neither allelic nor closely linked. A second type of mutation, allelic to one of the O restricted mutants, was also found. Clones homozygous for this mutant gene were selfe... |
4351179 | Determination of natural host taxonomy of RNA tumor viruses by molecular hybridization: application to RD-114, a candidate human virus. | The lysogenic bacteriophages and the RNA tumor viruses have in common the ability to add their genetic information to the genome of their host cells. The biological similarity extends further; data summarized here indicate that they both possess homology to the DNA of their uninfected indigenous hosts. Sharing of commo... |
4575285 | Mechanism of adsorption and eclipse of bacteriophage phi X174. II. Attachment and eclipse with isolated Escherichia coli cell wall lipopolysaccharide. | A mixture of aqueous phenol, choloroform, and ether extracts the lipopolysaccharides (LPS) from the phiX174-sensitive strain, Escherichia coli C/1, and resistant strains, C/phiX and K12. Interaction of the C/1 LPS with phiX in a starvation buffer containing 10(-3) M CaCl(2) at 37 C, but not at 15 C, results in a first-... |
4762111 | Biochemistry of Vibrio cholerae virulence. 3. Nutritional requirements for toxin production and the effects of pH on toxin elaboration in chemically defined media. | The investigations described in this report concern the metabolic and physiologic parameters governing cholera enterotoxin production in chemically defined growth media. The results indicate that the minimal nutritional requirements for growth of pathogenic Vibrio cholerae are the same as those for toxin production, an... |
4357602 | Differences in clinical and convalescent-phase antibodies of Rhesus monkeys infected with monkey pox, tanapox, and Yaba poxviruses. | Complement-fixing and complement-fixing inhibiting (CFI) antibodies were demonstrated in the clinical and convalescent stages, respectively, of rhesus monkeys infected with either monkey poxvirus, Tanapoxvirus, or Yaba poxvirus. Specificity of the CFI antibody was confirmed by its failure to cross-react with heterologo... |
24469413 | Sodium transport in Na(+)-rich Chlorella cells. | The rate of Na(+)/Na(+) exchange as measured with (24)Na(+) in Na(+)-rich cells of Chlorella pyrenoidosa is governed by a single rate constant and saturates with increasing external Na(+) concentration. The K mvalue for this process is 0.8 mM Na(+) and the maximum rate of exchange in illuminated cells is about 5 pmoles... |
4120609 | A polypeptide bacteriophage receptor: modified cell wall protein subunits in bacteriophage-resistant mutants of Bacillus sphaericus strain P-1. | Bacillus sphaericus strain P-1 has previously been shown to have a tetragonally arrayed (T layer) protein which forms the outer layer of the cell wall. The T layer was quantitatively extracted from whole cells by 6 M urea, and the T layer subunits were purified by electrophoresis of the extracts on acrylamide gels cont... |
4737320 | Isocoproporphyrin: nuclear-magnetic-resonance-and mass-spectral methods for the determination of porphyrin structure. | The use of ;shift reagents' in the determination of n.m.r. spectra, and of reductive alkylation in combination with g.l.c.-mass spectrometry, facilitates assignment of the order of substituents in porphyrins, and the application of these new techniques to isocoproporphyrin is described. |
4682899 | The axostyle of Saccinobaculus. I. Structure of the organism and its microtubule bundle. | The axostyle of the flagellate Saccinobaculus is a motile ribbon composed of microtubules, cross-bridged to form interconnected rows. We find a centriole-related row of dark-staining tubules near the nucleus at the anterior end of the axostyle. Other tubule rows bind parallel to this primary row, acquire ordered relati... |
16100956 | Fiber formation and myelinization of cultivated dissociated neurons from chicken dorsal root ganglia: an electron microscopic and scanning electron microscopic study. | Dissociated neurons from chicken embryo dorsal root ganglia were cultivated in Rose chambers for up to 5 weeks. Newly formed fibers appeared as single fibers or grouped in bundles. During the first week of cultivation microtubules and microfilaments were frequently observed. The diameters of the fibers increased progre... |
4620334 | Environmental radiation and the lung. | Environmental sources of radioactive materials and their relation to lung doses and lung burdens are described. The approaches used and the problems encountered in estimating lung doses are illustrated. Exposure to radon daughter products is contrasted to exposure to plutonium as particular examples of the hazards asso... |
4531037 | Electron diffraction of wet phospholipid bilayers. | The structure of fully hydrated dipalmitoyl lecithin single bilayers, and monolayers deposited on Formvar substrates are studied by electron diffraction, using a hydration stage fitted to an electron microscope. Selective area diffraction patterns of these films indicate that there are domains consisting of mosaics of ... |
4612532 | Termination point of replication of colicin E1 plasmid DNA in cell extracts. | Closed-circular monomeric molecules were one of the major products of replication of colicin E1 plasmid DNA in cell extracts. However, when the plasmid DNA synthesized in the reaction mixture was labeled for 3 min after 27 min of incubation, most of the label was found in open-circular molecules. The open-circular mole... |
4531019 | Biosynthesis of collagen crosslinks: increased activity of purified lysyl oxidase with reconstituted collagen fibrils. | Lysyl oxidase catalyzes the formation of crosslinking aldehydes in collagen and elastin. This report demonstrates that the enzyme has high activity with collagen precipitated as native fibrils, an apparent K(m) of 0.95 muM, and low activity toward either soluble forms such as denatured collagen, isolated alpha chain, o... |
4612021 | R6K plasmid replication: influence of chromosomal genotype in minicell-producing strains of Escherichia coli K-12. | Alkaline sucrose velocity sedimentation and cesium chloride-ethidium bromide equilibrium centrifugation have been used to determine the number of copies per chromosomal equivalent of the relaxedly replicating R6K plasmid (a conjugative plasmid conferring ampicillin and streptomycin resistance) in two minicell-producing... |
4215795 | Existence of a free form of a specific membrane lipoprotein in gram-negative bacteria. | The existence of a free form of a specific lipoprotein of molecular weight 7,200 was examined in the envelopes of several gram-negative bacteria. When the envelope proteins were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, distinct peaks were observed in Salmonella typhimurium, Serratia marces... |
4435960 | Augmentation of glucose transport in macrophages after particle ingestion. | Guinea pig and mouse peritoneal macrophages in culture transport glucose by a specific, saturable system with characteristics compatible with facilitated diffusion. Phagocytosis of killed staphylococci or polystyrene latex spheres results in a significant increase in uptake of 2-deoxy-d-glucose. Reciprocal plot analysi... |
16592206 | An electron-nuclear double resonance (ENDOR) study of the special pair model for photo-reactive chlorophyll in photosynthesis. | A comparison of hyperfine coupling constants obtained by electron-nuclear double resonance spectroscopy of in vitro monomer chlorophyll and bacteriochlorophyll free radicals with those of the photoesr (electron spin resonance) signal associated with light conversion in photosynthesis provides convincing support for the... |
4218959 | Soluble neutral and acid maltases in the suckling-rat intestine. The effect of cortisol and development. | The 100000g supernatants from 13-day-old suckling-rat intestinal homogenates contained 43.5% of the total intestinal maltase activity, compared with 7.1% in weaned adult rats aged 40 days. The soluble maltase activity was separated on Sepharose 4B into two quantitatively equal fractions at pH6.0, one containing a malta... |
4455688 | Co-transduction of plasmids mediating resistance to tetracycline and chloramphenicol in Staphylococcus aureus. | Independent plasmids mediating resistance either to tetracycline (Tc) or chloramphenicol (Cm) were transduced successively into Staphylococcus aureus strain 8325. From this doubly resistant donor strain, Tc was co-transduced with a frequency of 40 to 50% when Cm was selected. Co-transduction of Cm was 5 to 10% with Tc ... |
4142031 | Antigenic difference between polar montrichous and peritrichous flagella of Vibrio parahaemolyticus. | Polar monotrichous and peritrichous flagella of Vibrio parahaemolyticus were isolated and purified separately. On hydroxylapatite column chromatography, the flagellins of polar monotrichous flagella were eluted with a higher concentration of phosphate than those of peritrichous flagella. Gel diffusion tests showed an a... |
10793713 | A model for particulate structure in chromatin. | A model is proposed for the structure of nuclease-resistant chromatin particles. The model is novel in that it proposes that the DNA in such a particle is wound about a protein core, made up of the hydrophobic regions of histone molecules. |
4531005 | Self assembly of histone F2a1. | Purified F(2)a(1) histone molecules assemble into organized structures observable by electron microscopy. The basic structure observed at pH 8 and ionic strength of 0.15 has the shape of a bent rod with an average width of 22 A. The average circumferential length of the rod is 220 A and the average distance between the... |
4530995 | Tunable laser resonance raman spectroscopy of bacteriorhodopsin. | Bacteriorhodopsin is a rhodopsin-like protein found in the cell membrane of Halobacterium halobium. It shows an absorption maximum at 570 nm and, in the light, undergoes cyclic spectral changes which include a relatively long-lived complex absorbing maximally at 412 nm. Excitation profiles have been obtained with sever... |
4530994 | Biological membranes as bilayer couples. A molecular mechanism of drug-erythrocyte interactions. | We propose that membranes whose proteins and polar lipids are distributed asymmetrically in the two halves of the membrane bilayer can act as bilayer couples, i.e., the two halves can respond differently to a perturbation. This hypothesis is applied to the interactions of amphipathic drugs with human erythrocytes. It i... |
4373714 | Physical and physiological evidence for two phase transitions in cytoplasmic membranes of animal cells. | Electron spin resonance analysis of suspensions of animal cell plasma membranes consistently reveals four characteristic temperatures for lateral phase separations in the membrane lipids. Similar analysis of an aqueous dispersion of lipids extracted from these membranes reveals only two characteristic temperatures, ind... |
4610179 | Intermediates of bacteriophage MS2 assembly in vivo. | The in vivo process of virion assembly was studied in rifampin-treated, MS2-infected Escherichia coli during late times of infection-after 18 min postinfection. Differential sucrose gradient sedimentation of infected-cell lysates taken at various times after radioactive labeling indicated a definite temporal order of a... |
4607708 | The chemical composition of the cell wall of Chlamydomonas gymnogama and the concept of a plant cell wall protein. | Cell walls of Chlamydomonas gymnogama, shed during sexual mating, were collected and analyzed. Ultrastructural examination indicates that the walls are free of cytoplasmic contamination and that they exhibit a regular lamellate structure. The walls are composed of glycoprotein rich in hydroxyproline. The hydroxyproline... |
16811814 | Short-term memory in the pigeon: stimulus-response associations. | THREE PIGEONS PECKED FOR FOOD IN TWO EXPERIMENTS IN WHICH EACH TRIAL CONSISTED OF TWO PHASES: a study and a test phase. The study phase in Experiment I consisted of two stimulus-response pairs presented successively. Each pair consisted of the illumination of a left or right key (the stimulus) and a peck on the lighted... |
4609396 | Freeze-fracturing of nerve growth cones and young fibers. A study of developing plasma membrane. | Neural and non-neural cellular processes have been studied in organotypic cultures of spinal cord and olfactory bulb by means of the freeze-fracturing technique. Identification of specific cellular elements in replicas has been achieved by comparison with thin-sectioned material in which differences in shape and conten... |
4442715 | The use of hybrid somatic cells as an approach to mitochondrial genetics in animals. | We have studied the fate of parental mitochondrial DNA (mtDNA) in hybrid somatic cells derived by Sendai virus-induced fusion of human cells and mouse or rat cells. Many hybrid cell strains were obtained which contained sequences from both human and rodent mtDNA after 40 to 60 population doublings. Some strains were su... |
4853028 | Localization of coliphage MS2 A-protein. | The purification of coliphage MS2 dinitrophenol (DNP) conjugates provided a system for localization of the single molecule of A-protein in the capsid of the MS2 phage particle. Three A-protein preparations isolated from unconjugated MS2, overconjugated DNP-MS2, and purified 78S DNP-MS2 were tested for the presence of c... |
4136721 | Epithelial collagens and glycosaminoglycans in the embryonic cornea. Macromolecular order and morphogenesis in the basement membrane. | The embryonic corneal epithelium synthesizes both collagen and chondroitin sulfate and excretes them across the basement membrane into the subepithelial space where they assemble into a spiraling orthogonal matrix of fibrils. The assembly of collagen into fibrils is first apparent at the outer face of the basement memb... |
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